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Oozing and Filament Flow Issues  

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Stephen Schmitt
(@stephen-schmitt)
Active Member
Oozing and Filament Flow Issues

We just got our i3 MK3 a month or so ago, and once we replaced a part that broke during shipping, it has worked great.

But since we had one bad clog, probably from dropping the hot end temperature too low while trying to minimize stringing on a detailed model, we've had issues with the filament oozing during preheat and with what looks like inconsistent flow during printing. Mostly noticeable during the first layer.

We've also noticed the the when the head extracts that will leave a small peak of filament. Especially on the last layer.

I've tried adjusting the z-calibration, and I think it's in a good spot.

I haven't tried adjusting the extrusion modifier, yet, but I would think that if that was off it would affect the whole print.

Any suggestions on what I may be missing.

I'm a relative novice at this, so i'm attaching some photos of a couple of recent prints.

Posted : 28/08/2018 10:31 pm
bobstro
(@bobstro)
Illustrious Member
Re: Oozing and Filament Flow Issues

You do have some under-extrusion issues, but you're wise to hold off on modifying the slicer settings. Have you tried doing some cold-pulls to clean out any crud that may have built up with or since the clog?

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 28/08/2018 10:39 pm
Stephen Schmitt
(@stephen-schmitt)
Active Member
Topic starter answered:
Re: Oozing and Filament Flow Issues

I have not. Not familiar with doing a cold pull. I'll look into that.

Thank you.

Posted : 29/08/2018 3:34 am
Stephen Schmitt
(@stephen-schmitt)
Active Member
Topic starter answered:
Re: Oozing and Filament Flow Issues

Did a couple of cold pulls (was a little unnerving), and that seemed to help. Still have some under-extrusion, so did two more cold pulls today.

On the last pull I noticed an extra bulge in the pulled filament. Picture below.

Looking in the extruder body I noticed the PTFE tube appears to be touching the feed gear. I don't remember seeing much, if any, of the tube before. Is this right or do I need to disassemble the hot end and try and get the tube back where it belongs?

Posted : 30/08/2018 10:01 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Oozing and Filament Flow Issues

If you have PTFE available, might be an idea to make a new tube up, and fit it, whilst the extruder is apart...

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 30/08/2018 11:38 pm
Steve
(@steve-3)
Estimable Member
Re: Oozing and Filament Flow Issues

That looks like an relatively complex object. The first layer has to print the perimeters of around 100 small holes before filling the gaps. If any one of those perimeters comes loose, the print will fail. Pointy corners increase the possibility of something lifting. The print can still work, but you probably need to expect a few to fail. Don't walk away until several layers have been completed successfully. 🙂

Would it be possible to modify the design slightly? It looks like a drink coaster. Print the first few layers as a solid circle, then change colors to add the image. The last layers could either be a positive or negative image to create raised or inset letters. The solid first layer is easy to print and the top layers are PLA sticking to PLA, also easy to print.

Steve

Posted : 31/08/2018 6:55 pm
Saeros38
(@saeros38)
New Member
Re: Oozing and Filament Flow Issues

Hi there,

I have the exact same problem of filament oozing and flow issue. And I also noticed this PTFE tube touching my extruder gear. Did you solve you're problem yet ?

I think I might have pulled the PTFE tube up during my first filament unloading, because I was not ready to pull the filament when asked after the loud bip ...
I was printing pretty nicely after my assembly and things started to get ugly after this unload (left for the WE) and reload.

Any advice ?

Thanks !

Posted : 17/09/2018 9:38 pm
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